In tagging systems used by social networking sites, news sites, blogs, or e-commerce sites, each story or product is associated with user-defined tags. In keyword indexing systems used by search engines or glossary generators, each document is automatically associated with keywords via keyword extraction algorithm. Currently, the most popular method of visualizing tag data in aggregate is through the use of a tag cloud where a number of key words representing content of an associated document are displayed together. A tag cloud typically displays all tags in a system in alphabetical order, with font size determined by relative usage.
U.S. Pat. No. 6,226,645 B1 (Bae et al., 2001) discloses an Internet searching method. The disclosure describes a method for searching keyword described in web document and considering hyper link connection between searched keywords and constructing conceptional drawings which are made of keywords connected to searched words inputted by user.
US Pat. Pub. No. 20080005107 A1 (Funaki, 2008) relates to a technique for managing a keyword that is set to a file for the purpose of searching files. The disclosure describes a keyword management apparatus for managing a relationship among a plurality of keywords used to search a file. A keyword database stores a plurality of keywords and hierarchical relationship information by defining a hierarchical relationship among the keywords. A tree creation unit creates a plurality of keyword trees by utilizing the hierarchical relationship information. A designation unit designates a first keyword belonging to a first keyword tree by referring to the keyword database. A search unit searches for a second keyword that corresponds to the first keyword and belongs to a second keyword tree, and searches for a keyword on a layer above the second keyword obtained on the basis of the hierarchical relationship information. A display unit displays the search unit's search results.
US Pat. Pub. No. 20080313170 A1 (Kamen, 2008) pertains to technology used for data search, particularly data search over the Internet. As described in this disclosure, a method and apparatus, for any given keyword, generates a numeric value that defines keyword relevance based on the numeric value and importance of a keyword's forward link and back link keyword neighbors.
US Pat. Pub. No. 20100138428 A1 (Uchino et al., 2010) is directed to a keyword output apparatus and a keyword output method. In the apparatus and method, a commonness between expressions corresponding to a target keyword and each related keyword is calculated, and an association between a target keyword and each related keyword is calculated using a distance for each related keyword from the target keyword and the commonness, and a related keyword having a certain association is extracted as a same-region keyword in a same region as the target keyword. In the apparatus and method, a drawing including the target keyword and related keywords arranged according to the associations is output with the same-region keyword displayed distinguishably from other related keywords not included in the same region.